The device functions of semiconductor devices are significantly influenced by the numerical value of inherent capacitive elements, which numerical values are influenced by process parameters of respective manufacturing steps of the semiconductor device that result in the formation of those capacitive elements. Therefore, in such semiconductor devices, the device function may significantly depend on process parameter fluctuations that are difficult to control in a sufficiently precise manner.
A first type of capacitor element that may be relevant is a MOS capacitor element originating from the formation of a MOS (metal-oxide-semiconductor) structure in the manufacture of an MOS-type semiconductor element. In particular, the exact thickness of an oxide layer arranged on a semiconductor substrate and underlying a subsequently deposited metal layer significantly determines the capacitance value of a capacitor element of this type.
A second relevant type of capacitor element is a so-called MIM capacitor element, which is a specifically designed capacitor element, formed from a dedicated dielectric layer and metal layer. These layers are formed in the so-called BEOL (back-end-off-line) process for electrically connecting the respective transistor and resistor elements that beforehand were produced in the so-called FEOL(front-and-off-line) process.
A third type of relevant capacitor element is formed by using existing wiring layers, e.g., VPP structures, GRID structures or sandwich structures.
For all of these above mentioned capacitor elements, the respective process steps result in a typical fluctuation of the capacitance value of not less than 15%. However, for semiconductor elements the function of which is significantly determined by the capacitance value of such capacitor elements, a fluctuation value of the linear capacitance should be as low as about 10%.